1. Field of the Invention
The present invention relates to a hard disk drive, and more particularly, to formation of a push pin hole to implement a process of servo track writing.
2. Description of the Related Art
In information storage for a computer, a hard disk drive (HDD) reads data from a disk or writes data on the disk by use of a magnetic head. In order to write or read the data, a servo signal is previously recorded in a surface of the disk, which is referred to as a servo track write (STW).
In order to implement the servo track write, the hard disk drive is loaded onto an STW apparatus, and a head stack assembly (HSA) is pushed by a push pin provided to the STW apparatus, according to a predetermined program, so that the magnetic head records the servo signal on the surface of the disk. Accordingly, a base plate or cover plate of the hard disk drive is formed with a push pin hole through which the push pin passes.
FIGS. 1 and 2 are perspective views depicting a conventional base plate and cover plate mounted to an STW apparatus, respectively. A hard disk drive including a disk and an HSA should be mounted to the STW apparatus to implement a servo track write, while only the base plate and the cover plate are respectively shown in FIGS. 1 and 2 for clarity.
In order to mount the hard disk drive onto the STW apparatus 1, as shown in FIG. 1, the hard disk drive is firstly laid on a support 2, with a base plate 10 of the hard disk drive being in contact with the support 2. Alternatively, the hard disk drive is laid on the support 2, as shown in FIG. 2, with a cover plate 20 of the hard disk drive being in contact with the support 2. At that time, a push pin 8 is inserted into the hard disk drive through push pin holes 18 and 25 of the base plate 10 or cover plate 20.
Next, an x-direction push arm 6 and a y-direction push arm 7 are pushed toward an x-direction reference pin 4 and a y-direction reference pin 5, respectively, so that the base plate 10 or the cover plate 20 is positioned on a reference position. After the hard disk drive is mounted onto the STW apparatus 1, the push pin 8 is slowly moved in a longitudinal direction of the push pin hole 18 to push the HSA, so that a magnetic head records the servo signal on the surface of the disk. FIG. 1 further includes a z-direction.
Because of dimensional tolerance of the base plate 10 or cover plate 20, or operational error of a human or a robot implementing the mounting process, when the base plate 10 or the cover plate 20 is laid on the support 2, the push pin 8 does not penetrate through the push pin hole 18 or 25, and collides against a periphery of the hole, which damages the push pin 8 and deteriorates a quality of servo track write. In order to solve the above problem, the push pin hole 18 or 25 may be sufficiently enlarged, which deteriorates a sealing property of the hard disk drive and weakens rigidity of the base plate 10 or cover plate 20.